1. Field of the Invention
This invention relates generally to an elastomeric coupling and, more specifically, to an elastomeric coupling for rotatably connecting a pair of hubs to the ends of a pair of substantially inline rotatable shafts.
2. Description of the Prior Art
It is known to couple the ends of a pair of substantially inline rotatable shafts so that one shaft, driven by a motor, drives the other shaft by means of interengaging hubs connected to the ends of the respective shafts. One of such couplings available from Maurey Manufacturing Corp., Chicago, IL, includes a pair of hubs each having a central bore at one end for receiving therein the end of one of the respective shafts. The hubs are secured to the respective shafts for rotation therewith.
The other ends of the hubs are each formed with finger-like projections which are disposed to interfit to drivingly connect the hubs to one another. Since the hubs typically are made of steel or cast iron, a rubber spider member having a plurality of radially disposed and outwardly projecting fingers is disposed between the facing ends of the hubs, with the fingers of said spider sandwiched between the adjacently interfitting projections of the respective hubs. The spider serves as a cushioning compression member or spacer to reduce wear on the interfitting projections. The spider serves no function in mechanically coupling the hubs to one another. The arrangement is such that rotation of one of the hubs, imparted by rotation of the associated driven shaft, drives the other hub by means of the interfitting projections, thereby rotating the other shaft that is connected to the other hub. The spider also serves to cushion the shock of the interfitting projections during rotation of the hubs.
Although the spider affords some degree of flexibility in connecting the hubs to the ends of shafts that are not in perfect alignment, the ability to use the Maurey coupling in applications where the ends of the shafts are signifiantly misaligned is severely hampered. Also, since the spider is sandwiched between the hubs, it is not easy to detect when the spider becomes worn, otherwise ruptures, and is in need of replacement. The failure to timely replace a worn-out spider, that is, one that has lost a large measure of its cushioning function, can cause significant damage to the interfitting projections thereby requiring replacement of the hubs. Replacement of the spider also requires that at least one of the hubs be removed from the associated shaft to gain access to the worn spider, thereby increasing the down-time of the machines connected to said shafts during servicing of the hubs.
Another known coupling is that available from the Browning Manufacturing Division of Emerson Electric Co., Maysville, KY, and The Falk Corporation, Milwaukee, WI, in which the two hubs are mechanically coupled together by a continuous flexible grid. Specifically, each of the hubs has a plurality of grooves or passageways disposed radially around the perimeter of the hub, and extending longitudinally parallel to the axis of rotation. The grooves in one of the hubs are aligned with the corresponding grooves in the other hub, whereupon a ring-like flexible grid made of spring steel is positioned within the rows of aligned grooves. A grease lubricant is packed over the grid, and a cover is fitted around and secured to the coupled hubs. Prior to joining the two hubs together, the opposite ends of the hubs were first joined to the ends of the respective shafts in conventional manner.
The respective grids in the Browning and Falk couplings do, indeed, serve to couple the two hubs to one another, and also provide some degree of flexibility in connecting the ends of misaligned shafts. However, assembly of these types of couplings requires a fair amount of skill. Also, it is necessary to first disassemble the cover from the coupling and remove the grease lubricant in order to inspect the grid for possible wear. This, again, results in unwarranted down-time in the machines connected to the shafts.
The present invention provides an improved coupling arrangement, as compared to known couplings, which affords increased flexibility to accommodate parallel or angular misalignment of the shafts, and which is easily assembled and serviced as the need arises.